Test the V parser, by parsing each .v file in each PATH,
as if it was typed character by character by the user.

Usage:
  v test-parser [PATH1 PATH2 ...]

A PATH can be either a folder, or a specific .v file.
Note: you *have to quote* the PATH, if it contains spaces/punctuation.

The sources are parsed repeatedly, in gradually shorter prefixes, to
expose parser panics, errors and hangs. Most of the shown options are
meant for its internal worker processes:

Options:
  -h, --help            Show help/usage screen.
  -v, --verbose         Be more verbose.
  -S, --silent          Do not print progress at all.
  -L, --linear          Print a linear progress log. Suitable for CI.
  -E, --show_source     Print the partial source code that caused a
                        fault/panic in the parser.
  -s, --progress_ms     Print a status report periodically; the period
                        is given in milliseconds (default 500).

The worker flags (-w, -c, -t, -p) are used internally by the supervisor
process, when it spawns workers to parse individual source files
safely, under a timeout.
